Structured light projector and electronic device including the same

ABSTRACT

Provided is a structured light projector including a light source configured to emit light, and a nanostructure array configured to form a dot pattern based on the light emitted by the light source, the nanostructure array including a plurality of super cells each respectively including a plurality of nanostructures, wherein each of the plurality of super cells includes a first sub cell that includes a plurality of first nanostructures having a first shape distribution and a second sub cell that includes a plurality of second nanostructures having a second shape distribution.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based on and claims the benefit of U.S. ProvisionalPatent Application No. 62/758,064, filed on Nov. 9, 2018 in the UnitedStates Patent and Trademark Office, and claims priority from KoreanPatent Application No. 10-2019-0017960, filed on Feb. 15, 2019, in theKorean Intellectual Property Office, the disclosures of which areincorporated herein by reference in their entireties.

BACKGROUND 1. Field

Example embodiments of the present disclosure relate to a structuredlight projector and an electronic device including the same.

2. Description of the Related Art

Recently, in relation to recognition of an object such as a human,things, etc., the need to accurately identify a shape, a position,movement, etc., of the object has increased for precisethree-dimensional (3D) shape recognition. As a method to increaseaccuracy of 3D shape recognition, a 3D sensing technique usingstructured light has been developed, enabling a more precise motionrecognition.

A structured light system has to be capable of forming a required dotpattern, and also, to be coupled with various electronic devices,miniaturization and high resolution of the structured light system arerequired. To produce structured light, an optical part such as adiffractive optical element (DOE) may be used. However, a volume of theoptical part affects design precision and manufacturing requirements.

SUMMARY

One or more example embodiments provide a structured light projector andan electronic device including the same.

Additional aspects will be set forth in part in the description whichfollows and, in part, will be apparent from the description, or may belearned by practice of example embodiments.

According to an aspect of an example embodiment, there is provided astructured light projector including a light source configured to emitlight, and a nanostructure array configured to form a dot pattern basedon the light emitted by the light source, the nanostructure arrayincluding a plurality of super cells each respectively including aplurality of nanostructures, wherein each of the plurality of supercells includes a first sub cell that includes a plurality of firstnanostructures having a first shape distribution and a second sub cellthat includes a plurality of second nanostructures having a second shapedistribution.

The light source may include a plurality of light-emitting elements.

The plurality of light-emitting elements and the plurality of supercells may be provided in two-dimensional periodic lattices,respectively.

A ratio of a lattice constant of the plurality of light-emittingelements to a lattice constant of the plurality of super cells may be arational number.

The two-dimensional periodic lattices of the plurality of light-emittingelements and the two-dimensional periodic lattices of the plurality ofsuper cells may have a same shape and different sizes.

The two-dimensional periodic lattices of the plurality of light-emittingelements and the two-dimensional periodic lattices of the plurality ofsuper cells may have a same shape and a same size.

A distance between the light source and the nanostructure array may bean integer multiple of C²/2λ, in which a lattice constant of the supercell is C and a central wavelength of the light emitted by the lightsource is λ.

The first shape distribution and the second shape distribution may bedifferent from each other.

The first sub cell and the second sub cell may have equal areas.

The super cell may further include k sub cells respectively including ak^(th) nanostructure provided with a k^(th) shape distribution, in whichk is an integer between 3 and N and N is an integer greater than 3.

The first through N^(th) sub cells included in the super cell may beprovided in a two dimensional periodic lattice.

Each of the first through N^(th) sub cells included in the super cellmay have an area corresponding to an equally divided area of the supercell.

First through N^(th) shape distributions of a plurality of firstnanostructures through a plurality of N^(th) nanostructures included ineach of the first through N^(th) sub cells may be different from eachother.

Phase profiles of the first through N^(th) sub cells may be associatedwith each other based on a predetermined rule, and each of the firstthrough N^(th) sub cells may be configured to modulate a phase ofincident light based on the phase profiles of the first through N^(th)sub cells, respectively.

A phase profile for an m^(th) sub cell may include a local phase profilethat is common to the first through N^(th) sub cells and a global phaseprofile corresponding to a position of the super cell in which them^(th) sub cell is included, in which m is an integer from 1 to N and Nis an integer greater than or equal to 3.

The first nanostructure and the second nanostructure, respectively, mayhave shape dimensions that are less than a wavelength of the lightemitted by the light source.

A pitch of the plurality of first nanostructures and a pitch of theplurality of second nanostructures, respectively, may be less than orequal to ½ of the wavelength of the light emitted by the light source.

A height of each first nanostructure and a height of each secondnanostructure, respectively, may be less than or equal to ⅔ of thewavelength of the light emitted from the light source.

The first nanostructure and the second nanostructure, respectively, mayinclude a material having a refractive index that is different from arefractive index of a surrounding material by 0.5 or more.

The dot pattern may include a random pattern, and the random pattern mayinclude a plurality of dots forming a cluster, the cluster beingregularly provided.

According to another aspect of an example embodiment, there is providedan electronic device including a structured light projector including alight source configured to emit light, and a nanostructure arrayconfigured to form a dot pattern based on the light emitted by the lightsource, the nanostructure array including a plurality of super cellseach respectively including a plurality of nanostructures, wherein eachof the plurality of super cells includes a first sub cell that includesa plurality of first nanostructures having a first shape distributionand a second sub cell that includes a plurality of second nanostructureshaving a second shape distribution, a first sensor configured to receivelight reflected by an object that is irradiated by light emitted by thestructured light projector, and a processor configured to obtain firstinformation regarding a depth position of the object based on the lightreceived by the first sensor.

The electronic device may further include a second sensor configured toreceive the light reflected by the object, wherein the processor isfurther configured to obtain second information regarding the depthposition of the object based on the light received by the second sensor.

The processor may be further configured to obtain depth information ofthe object based on at least one of the first information and the secondinformation.

According to yet another aspect of an example embodiment, there isprovided a structured light projector including a light sourceconfigured to emit light, the light source including a plurality oflight-emitting elements, and a nanostructure array configured to form adot pattern based on the light emitted by the light source and includinga plurality of super cells, each of the plurality of super cellsincluding a plurality of sub cells, wherein each of the plurality of subcells is configured to modulate a phase of light emitted by the lightsource based on a phase profile of each of the plurality of sub cells.

The phase profile of each of the plurality of sub cells may be set basedon a predetermined rule corresponding to the dot pattern.

The plurality of light-emitting elements and the plurality of supercells may be provided in two-dimensional periodic lattices,respectively, and the two-dimensional periodic lattices of the pluralityof light-emitting elements and the two-dimensional periodic lattices ofthe plurality of super cells may have a same shape.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and/or other aspects will become apparent and more readilyappreciated from the following description of example embodiments, takenin conjunction with the accompanying drawings in which:

FIG. 1 is a cross-sectional view illustrating a structure of astructured light projector according to an example embodiment;

FIG. 2 is a plan view showing that a pattern of a nanostructure arrayincluded in a structured light projector of FIG. 1 that includes supercells including a plurality of sub cells;

FIG. 3 is a plan view showing in detail a pattern including sub cellsand super cells of a nanostructure array by enlarging a partial regionof FIG. 2;

FIG. 4 is a plan view illustrating arrangement of a plurality oflight-emitting elements included in a light source included in astructured light projector of FIG. 1;

FIG. 5 is a plan view enlarging a partial region of a structured lightprojector of FIG. 1, which illustrates a corresponding relation betweena super cell and a light-emitting element;

FIG. 6 conceptually shows that sub cells included in a super cell formdifferent phase profiles;

FIG. 7 illustrates a random pattern of structured light formed by asuper cell;

FIG. 8 illustrates structured light in a quasi-random dot pattern formedby a structured light projector of FIG. 1;

FIG. 9 is a cross-sectional view showing in detail a first sub cellincluded in a nanostructure array of a structured light projector ofFIG. 1;

FIG. 10 is a cross-sectional view showing in detail a second sub cellincluded in a nanostructure array of a structured light projector ofFIG. 1;

FIGS. 11A through 11E are perspective views showing example shapes of ananostructure shown in FIGS. 9 and 10;

FIG. 12 is a plan view showing a pattern of a nanostructure arrayincluded in a structured light projector according to an exampleembodiment;

FIG. 13 is a plan view showing arrangement of a plurality oflight-emitting elements included in a light source employed in astructured light projector including a nanostructure array of FIG. 12;

FIG. 14 is a block diagram illustrating a schematic structure of anelectronic device according to an example embodiment; and

FIG. 15 is a block diagram illustrating a structure of an electronicdevice according to an example embodiment.

DETAILED DESCRIPTION

Reference will now be made in detail to example embodiments of which areillustrated in the accompanying drawings, wherein like referencenumerals refer to like elements throughout, and each element may beexaggerated in size for clarity and convenience of a description. Inthis regard, the example embodiments may have different forms and shouldnot be construed as being limited to the descriptions set forth herein.Accordingly, the example embodiments are merely described below, byreferring to the figures, to explain aspects. As used herein, the term“and/or” includes any and all combinations of one or more of theassociated listed items. Expressions such as “at least one of,” whenpreceding a list of elements, modify the entire list of elements and donot modify the individual elements of the list. For example, theexpression, “at least one of a, b, and c,” should be understood asincluding only a, only b, only c, both a and b, both a and c, both b andc, or all of a, b, and c.

The following example embodiments are merely illustrative, and variousmodifications may be possible from the embodiments.

An expression such as “above” or “on” may include not only the meaningof “immediately on in a contact manner”, but also the meaning of “on ina non-contact manner”.

When it is assumed that a certain part includes a certain component, theterm “including” or “comprising” means that a corresponding componentmay further include other components unless a specific meaning opposedto the corresponding component is written.

The term used in the embodiments such as “unit” or “module” indicates aunit for processing at least one function or operation, and may beimplemented in hardware, software, or in a combination of hardware andsoftware.

FIG. 1 is a cross-sectional view illustrating a structure of astructured light projector according to an example embodiment. FIG. 2 isa plan view showing that a pattern of a nanostructure array included inthe structured light projector of FIG. 1 that includes super cellsincluding a plurality of sub cells, and FIG. 3 is a plane view showing apattern including sub cells and super cells of the nanostructure arrayby enlarging a partial region of FIG. 2. FIG. 4 is a plan viewillustrating arrangement of a plurality of light-emitting elementsincluded in a light source included in the structured light projector ofFIG. 1.

A structured light projector 100 may include a light source 120 and ananostructure array 140 that forms structured light having a dot patternby light emitted from the light source 120.

The nanostructure array 140 may include a plurality of nanostructures.Arrangement of the plurality of nanostructures may form a hierarchicalstructure of nanostructure-subcell-supercell. For example, a sub cellincludes a plurality of nanostructures, and a plurality of sub cellsform a super cell. The super cell 145 is repetitively arranged on thenanostructure array 140.

Referring to FIG. 3, the super cell 145 may include k^(th) sub cell SB_k(where k is an integer from 1 to 9). However, the number of sub cells,9, is merely an example, and embodiments are not limited thereto. Thenumber of sub cells may be an integer greater than or equal to 2. Thek^(th) sub cell SB_k (k is an integer from 1 to 9) may be indicated by{circle around (k)} The super cell 145 including the k sub cells SB_k (kis an integer from 1 to 9) may be arranged in a two-dimensional (2D)periodic lattice form. As shown in FIG. 3, the periodic lattice may be aparallelogram shape in which lattice constants in two directions areequal to C1.

The light source 120 may include an array of a plurality oflight-emitting elements 122. However, embodiments are not limitedthereto, and the light source 120 may be a single light source.

When the light source 120 includes the array of the plurality oflight-emitting elements 122, arrangement of the plurality oflight-emitting elements 122 may be identical or similar to arrangementof the super cell 145. When a plurality of super cells 145 are arrangedin a 2D periodic lattice form, the plurality of light-emitting elements122 may also be arranged in a corresponding 2D periodic lattice form.For example, the plurality of super cells 145 and the plurality oflight-emitting elements 122 may be arranged in the 2D periodic latticesof the same shape or similar shapes. The plurality of light-emittingelements 122 and the plurality of super cells 145 may be arranged in the2D periodic lattices having the same shape and the same size. Theplurality of light-emitting elements 122 and the plurality of supercells 145 may also be arranged in the 2D periodic lattices having thesame shape and different sizes. However, embodiments are not limitedthereto. An optimal optical distance between the nanostructure array 140and the light source 120 may be determined based on an arrangement pitchbetween each of the plurality of light-emitting elements 122. Theplurality of light-emitting elements 122 and the plurality of supercells 145 may be arranged in the 2D periodic lattices having differentshapes and different sizes.

The light-emitting element 122 may be a light-emitting diode (LED) or alaser diode. The light-emitting element 122 may be a vertical cavitysurface emitting laser (VCSEL). The light-emitting element 122 mayinclude an active layer including a Group III-V semiconductor materialor a Group II-VI semiconductor material and having a multi-quantum wellstructure. However, embodiments are not limited thereto. Thelight-emitting element 122 may emit laser light of about 850 nm or 940nm, or light in a near infrared light or visible light wavelength band.However, the wavelength of the light emitted from the light-emittingelement 122 is not limited thereto, and the light-emitting element 122emitting light in a desired wavelength band may be used.

The light-emitting elements 122 may be separately controlled. Opticalcharacteristics, for example, a wavelength, an angular spectrum of awave front, etc., of the light-emitting elements 122 may be identical.However, embodiments are not limited thereto, and the light-emittingelements 122 having different optical characteristics may be employedtogether.

As illustrated in FIG. 4, the plurality of light-emitting elements 122may be arranged in a parallelogram form, in which the lattice constantsin the two directions are C2. The sizes of periodic lattices, i.e., thelattice constants in the two directions of arrangement of the pluralityof super cells 145 and arrangement of the plurality of light-emittingelements 122 may not be the same as each other. A ratio of the latticeconstant C1 for arrangement of the plurality of super cells 145 to thelattice constant C2 for arrangement of the plurality of light-emittingelements 122 may be a rational value. For example, C1/C2 is not limitedto an integer, and may have an arbitrary rational value. Arrangement ofthe plurality of light-emitting elements 122 may have a relation inwhich one or more light-emitting elements 122 correspond to one supercell 145. However, embodiments are not limited thereto, and the numberof light-emitting elements 122 may be less than the number of supercells 145.

The plurality of sub cells SB_k (k is an integer from 1 to 9) may havean equal area, respectively. Each sub cell SB_k (k is an integer from 1to 9) may have an area obtained by equally dividing the area of thesuper cell 145. The super cell 145 and the sub cell SB_k (k is aninteger from 1 to 9) may have the same shape. Although the sub cell SB_k(k is an integer from 1 to 9) is illustrated as a regular hexagon andthe super cell 145 is illustrated as a parallelogram in FIG. 3, thisillustration is an example and the sub cell SB_k (k is an integer from 1to 9) may also have a parallelogram shape. The uniformity in intensitybetween dots of a dot pattern of structured light may be maximized byequalizing the areas of the sub cells SB_k (k is an integer from 1 to9). However, embodiments are not limited thereto, and area distributionbetween the sub cells SB_k (k is an integer from 1 to 9) in the supercell 145 may not be uniform. The plurality of sub cells SB_k (k is aninteger from 1 to 9) may have different areas, respectively. Theplurality of sub cells SB_k (k is an integer from 1 to 9) may havedifferent shapes, respectively. The super cell 145 and the sub cell SB_k(k is an integer from 1 to 9) may have different shapes. The shapes maybe determined considering a structured light pattern required based onan application to which the structured light projector 100 is to beapplied.

An optical distance OPD between the light source 120 and thenanostructure array 140 may be determined to be a proper distance inwhich when light from the light source 120 forms a dot pattern whilepassing through the nanostructure array 140, each dot is clearly formed.For example, the optical distance OPD may be set to a distance in whicha clear dot is formed by self-imaging, Talbot effect, etc.

When the plurality of light-emitting elements 122 and the plurality ofsuper cells 145 are arranged in the 2D periodic lattices having the sameshape and the same size, the optical distance OPD may be an integermultiple of C²/2λ for a lattice constant C of the super cell 145, acentral wavelength λ of light from the light source 120, and arefractive index 1 of a medium between the light source 120 and thenanostructure array 140.

FIG. 5 is a plan view enlarging a partial region of the structured lightprojector 100 of FIG. 1, illustrating a corresponding relation betweenthe super cell 145 and the light-emitting element 122.

As shown in FIG. 5, one light-emitting element 122 may correspond to onesuper cell 145. A position in which one light-emitting element 122corresponds to one super cell 145 is not limited to an illustratedposition {circle around (1)}. As long as arrangement of thelight-emitting elements 122 has a periodic lattice form having the sameshape as that of arrangement of the super cells 145, the light-emittingelement 122 and the super cell 145 may correspond to each other inanother position in the super cell 145.

FIG. 6 conceptually shows that sub cells included in a super cellforming different phase profiles, and FIG. 7 illustrates a randompattern of structured light formed by a super cell.

The k^(th) sub cells SB_k (k is an integer from 1 to 9) included in thesuper cell 145 may have the same phase profile or different phaseprofiles for modulating a phase of incident light. Different phaseprofiles are illustrated using different slash lines PL in the sub cellsSB_k. Phase profiles of the k sub cells SB_k (k is an integer from 1 to9) may be associated with each other according to a rule depending on adot pattern to be formed. For example, when the k sub cells SB_k (k isan integer from 1 to 9) share the same lens phase profile, structuredlight in a periodic dot pattern may be formed.

The phase profiles of the k sub cells SB_k (k is an integer from 1 to 9)may include a local phase profile component that is common among the ksub cells SB_k (k is an integer from 1 to 9) and a global phase profilecomponent associated with a relative position of the super cell 145 inwhich the k^(th) sub cell SB_k is included. The local phase profile maybe a phase profile having center of each k^(th) sub cell SB_k (k is aninteger from 1 to 9) a reference thereof. The global phase profileassociated with the relative position of the super cell 145 in which thek^(th) sub cell SB_k (k is an integer from 1 to 9) is included isassociated with a 2D coordinate space position of the super cell 145 inwhich the k^(th) sub cell SB_k (k is an integer from 1 to 9) isincluded. For example, letting an interval between the diagonal lines PLbe a period of a global linear phase profile, the global phase profileis determined based on wavevectors (k_(x), k_(y)) corresponding theretoand position coordinates (x, y) on a 2D space on which nanostructures ofa nanostructure array are arranged. A phase difference between the k subcells of different super cells is determined based on a relativeposition of the super cell and a wavevector corresponding to the k^(th)sub cell SB_k. Different sub cells may have different wavevectors.

The local phase profile may determine an intensity distribution of a dotpattern, light spread, etc. The global phase profile may shift aposition of the dot pattern to be formed by the local phase profile. Anamount and a direction of the shift may correspond to a size and adirection of a wavevector of the global linear phase profile.

Referring to FIG. 7, structured light SL may include a plurality ofrepeated random patterns RP. The illustrated random pattern RPillustrates the dot pattern formed by one super cell 145. A uniquewavevector set of the k^(th) sub cell SB_k (k is an integer from 1 to 9)may be set such that positions of dots of the structured light SL do notoverlap. The position, intensity distribution, size, etc., of the dotmay be changed for a desired form by designing phase profiles of the ksub cells SB_k (k is an integer from 1 to 9).

FIG. 8 illustrates structured light in a quasi-random dot pattern formedby a structured light projector of FIG. 1.

Herein, the quasi-random dot pattern indicates a pattern in which eachrandom pattern including a plurality of dots forms a cluster that isarranged according to a rule.

FIG. 9 is a cross-sectional view showing in detail a first sub cellincluded in a nanostructure array of a structured light projector ofFIG. 1, and FIG. 10 is a cross-sectional view showing in detail a secondsub cell included in a nanostructure array of a structured lightprojector of FIG. 1. FIGS. 11A through 11E are perspective views showingin detail example shapes of a nanostructure shown in FIGS. 9 and 10.

A first sub cell SB_1 may include a substrate SU and a plurality offirst nanostructures NS1 formed on the substrate SU. The firstnanostructure NS1 may have a column shape having a cross-sectional widthD1 and a height H1. The first nanostructure NS1 may have a shapedimension of a sub wavelength, i.e., a shape dimension less that acentral wavelength λ of light emitting by the light source 120. Theheight H1 of the first nanostructure NS1 may be less than or equal to ⅔of the wavelength A. An arrangement pitch of the plurality of firstnanostructures NS1 may be less than or equal to ½ of the wavelength λ.

A second sub cell SB_2 may include the substrate SU and a plurality ofsecond nanostructures NS2 formed on the substrate SU. The secondnanostructure NS2 may have a column shape having a cross-sectional widthD2 and a height H2. The height H2 of the second nanostructure NS2 may beless than or equal to ⅔ of the wavelength λ. An arrangement pitch of theplurality of first nanostructures NS2 may be less than or equal to ½ ofthe wavelength λ.

A shape distribution of the plurality of first nanostructures NS1 and ashape distribution of the plurality of second nanostructures NS2 may bedifferent from each other. Herein, shape distribution may be any one ormore of a shape, a size, an arrangement pitch, shape distribution foreach position, size distribution for each position, and arrangementpitch distribution for each position, with respect to each of the firstnanostructure NS1 and the second nanostructure NS2. The shapedistribution of the plurality of first nanostructures NS1 and the shapedistribution of the plurality of second nanostructures NS2 may bedetermined in a dot pattern to be formed by a super cell including thefirst sub cell SB_1 and the second sub cell 562.

FIGS. 9 and 10 illustrate two sub cells, i.e., the first sub cell SB_1and the second sub cell SB_2. For a super cell including N sub cells,first through N^(th) shape distributions of a plurality of firstnanostructures through a plurality of N^(th) nanostructures included inthe first through Nth sub cells, respectively, may be different from oneanother. According to an example embodiment, nanostructure shapedistributions of at least two sub cells may be different from oneanother.

As such, a plurality of sub cells forming a super cell may have phaseprofiles that are associated with each other according to a ruledepending on a dot pattern to be formed by the super cell. Nanostructureshape distribution of each sub cell is determined to implement such aphase profile. Although each of the plurality of first nanostructuresNS1 and each of the plurality of second nanostructures NS2 areillustrated as having the same shape, size, and interval, respectively,example embodiments are not limited thereto. When a super cell includesN sub cells, the k^(th) nanostructure shape distribution of the k^(th)sub cell SB_k (k is an integer from 1 to 9) may be determined toimplement a desired phase profile.

The first nanostructure NS1 and the second nanostructure NS2 may includea material having a refractive index that is different from a refractiveindex of a surrounding material by 0.5 or more. For example, thesubstrate SU supporting the first nanostructure NS1 and the substrate SUsupporting the second nanostructure NS2 may include a material having arefractive index that is different from a refractive index of the firstnanostructure NS1 and a refractive index of the second nanostructureNS2. A difference between the refractive indices of the substrate SU andthe first nanostructure NS1 and a difference between the refractiveindices of the substrate SU and the second nanostructure NS2 may begreater than or equal to 0.5. The refractive indices of the firstnanostructure NS1 and the second nanostructure NS2 may be higher thanthe refractive index of the substrate SU, but example embodiments arenot limited thereto. For example, the refractive indices of the firstnanostructure NS1 and the second nanostructure NS2 may be lower than therefractive index of the substrate SU.

The substrate SU may include any one material among glass (fused silica,BK7, etc.), quartz, polymer (polymethyl methacrylate (PMMA), SU-8,etc.), and plastic, or may be a semiconductor substrate. The firstnanostructure NS1 and the second nanostructure NS2 may include at leastone of c-Si, p-Si, a-Si, Group III-V compound semiconductor (galliumphosphide (GaP), gallium nitride (GaN), gallium arsenide (GaAs), etc.),silicon carbide (SiC), titanium oxide (TiO2), or silicon nitride (SiN).

The first nanostructure NS1 and the second nanostructure NS2 may have acylindrical shape with a diameter D and the height H as illustrated inFIG. 11A, or a square prism shape with a side length D and the height Has illustrated in FIG. 11B. The first nanostructure NS1 and the secondnanostructure NS2 may have a column shape having an asymmetric crosssection. The first nanostructure NS1 and the second nanostructure NS2may have an elliptic column shape having different lengths of a majoraxis Dx and a minor axis Dy and the height H as illustrated in FIG. 11C,have a rectangular prism shape having different lengths of a width Dxand a length Dy and the height H as illustrated in FIG. 11D, and a prismshape having a cross-shape cross section with different lengths of thewidth Dx and the length Dy and the height H as illustrated in FIG. 11E.

FIG. 12 is a plan view showing a pattern of a nanostructure arrayincluded in a structured light projector according to an exampleembodiment.

A plurality of super cells 245 of a nanostructure array 240 may bearranged in a periodic lattice form having a rectangular shape. Alattice constant C3 in a horizontal direction X and a lattice constantC4 in a vertical direction Y may be equal to or different from eachother. Sub cells SB_k (k is an integer from 1 to 9) included in thesuper cell 245 may be arranged in a periodic lattice form having arectangular shape. The super cell 245 is illustrated as including ninesub cells SB_k, but this is merely an example, such that two or more oranother number of sub cells may be included therein.

FIG. 13 is a plan view showing arrangement of a plurality oflight-emitting elements included in a light source employed in astructured light projector including a nanostructure array of FIG. 12.

When a light source 220 includes a plurality of light-emitting elements222 in a structured light projector including the nanostructure array240 as illustrated in FIG. 12, the plurality of light-emitting elements222 may be arranged in a periodic lattice form having a rectangularshape like the super cells 245 of the nanostructure array 240. A latticeconstant in the horizontal direction X and a lattice constant in thevertical direction Y for arrangement of the plurality of light-emittingelements 222 may be C5 and C6, respectively.

When arrangement of the super cells 245 of the nanostructure array 240is in a square lattice form in which C3 and C4 are equal to each other,arrangement of the plurality of light-emitting elements 122 may also bein a square lattice form in which C5 and C6 are equal to each other.C3/C4 may be equal to C5/C6. One or more light-emitting elements 222 maycorrespond to one super cell 245, that is, the number of plurallight-emitting elements may be equal to or greater than the number ofsuper cells 245. However, example embodiments are not limited thereto,and the number of plural light-emitting elements 222 may be less thanthe number of super cells 245.

FIG. 14 is a block diagram illustrating a structure of an electronicdevice according to an example embodiment.

An electronic device 500 may include a structured light projector 510configured to radiate structured light SL to an object OBJ, a sensor 530configured to receive the light reflected from the object OBJ that isirradiated with structured light SL, and a processor 550 configured toperform calculation for obtaining shape information of the object OBJfrom light Lr received from the sensor 530.

The structured light projector 510 may employ the above-describedstructured light projector 100. The structured light projector 510 mayform structured light in a desired dot pattern by using a shape of ahierarchical structure formed of a nanostructure-sub cell-super cell ofa nanostructure array and a light source having arrangementcorresponding thereto, thus forming structured light in a desired dotpattern. In this hierarchical structure, the number of plural sub cellsincluded in a super cell or a relationship between phase profiles of thesub cells may depend on an application in which information about theobject OBJ is used.

The sensor 530 may sense the structured light Lr reflected by the objectOBJ. The sensor 530 may include an array of optical detection elements.The sensor 530 may further include a spectroscopy device for analyzinglight reflected from the object OBJ based on a wavelength.

The processor 550 may obtain depth information regarding the object OBJby comparing the structured light SL irradiated to the object OBJ withthe light Lr reflected from the object OBJ, and analyze 3D shape,position, movement, etc., of the object OBJ from the obtained depthinformation. A dot pattern of the structured light SL generated in thestructured light projector 510 may be a mathematically coded pattern touniquely have an angle and a direction of rays of light and positioncoordinates of a bright point and a dark point reaching a focal plane.This pattern may be formed by a detailed shape of the hierarchicalstructure in which nanostructures included in the structured lightprojector 510 form sub cells and super cells. When light in this patternis reflected from the object OBJ in a 3D shape, a pattern of thereflected light Lr has a shape changed from the pattern of theirradiated structured light SL. Such patterns may be compared and acoordinate-specific pattern may be tracked to extract the depthinformation of the object OBJ, such that 3D information associated withshape, depth, and movement of the object OBJ may be extracted.

The processor 550 may control an operation of the electronic device 500overall, for example, an operation of the sensor 530 or driving of alight source included in the structured light projector 510.

The electronic device 500 may further include a memory. A calculationmodule programmed to allow the processor 550 to execute calculation forextraction of 3D information regarding the object OBJ, and other datanecessary for the calculation may be stored in the memory.

Optical elements for adjusting a direction of the structured light SLfrom the structured light projector 510 toward the object OBJ orperforming further modulation with respect to the structured light SLmay be further arranged between the structured light projector 510 andthe object OBJ.

A calculation result of the processor 550, i.e., information about theshape and the position of the object OBJ may be transmitted to anotherunit or another electronic device. For example, such information may beused in another application module stored in the memory may be used. Theother electronic device to which the calculation result is transmittedmay be a display device or a printer. The other electronic device mayalso be, but not limited to, an autonomous device such as an unmannedvehicle, an autonomous vehicle, a robot, a drone, etc., a smart phone, asmart watch, a cellular phone, a personal digital assistant (PDA), alaptop, a personal computer (PC), various wearable devices, other mobileor non-mobile computing devices, Internet of Things (IoT) devices, orthe like.

The electronic device 500 may be a depth camera or a structured lightcamera that obtains a depth image of the object OBJ. The electronicdevice 500 may also be, but is not limited to, an autonomous device suchas an unmanned vehicle, an autonomous vehicle, a robot, a drone, etc., asmart phone, a smart watch, a cellular phone, a PDA, a laptop, a PC,various wearable devices, other mobile or non-mobile computing devices,IoT devices, or the like, which uses the depth information of the objectOBJ.

FIG. 15 is a block diagram illustrating a schematic structure of anelectronic device according to an example embodiment.

An electronic device 600 may include a structured light projector 610configured to irradiate the structured light SL to the object OBJ, afirst sensor 630 and a second sensor 640 configured to sense light fromthe object OBJ, and a processor 650 configured to perform calculationfor obtaining shape information of the object OBJ by analyzing lightreceived from at least one of the first sensor 630 or the second sensor640.

The electronic device 600 according to the example embodiment isdifferent from the electronic device 500 of FIG. 14 in that theelectronic device 600 includes the first sensor 630 and the secondsensor 640 that are arranged in different positions to receive lightreflected from the object OBJ. Information at different viewpoints,associated with depth positions, may be obtained by the first sensor 630and the second sensor 640 arranged in different positions with respectto the object OBJ. The processor 650 may calculate depth information byusing information at a plurality of viewpoints, thus having improvedaccuracy.

The electronic device 600 may be referred to as an active stereo camerain that the information at the plurality of viewpoints are obtained byusing structured light rather than general lighting.

The first sensor 630, the structured light projector 610, and the secondsensor 640 may be arranged in series or arranged spaced apart by acertain distance. Although the structured light projector 610 isillustrated as being arranged between the first sensor 630 and thesecond sensor 640, this illustration is an example. The first sensor 630may be arranged between the second sensor 640 and the structured lightprojector 610 or may be arranged differently.

The first sensor 630 and the second sensor 640 each may include an arrayof optical detection elements. The first sensor 630 and the secondsensor 640 may be arranged in different positions relative to thestructured light projector 610, and thus may have different detailedinformation of reflected light sensed from the object OBJ. The firstsensor 630 may receive reflected light L_(r1), and the second sensor 640may receive reflected light L_(r2).

The processor 650 may calculate first information regarding a depthposition of the object OBJ by analyzing the reflected light L_(r1)received from the first sensor 630, and calculate second informationregarding a depth position of the object OBJ by analyzing the reflectedlight L_(r2) received from the second sensor 640. The processor 650 maycalculate depth information regarding the object OBJ by using any one orall of the first information and the second information.

The electronic device 600 according to the example embodiment mayimprove accuracy when compared to the example embodiment including onesensor. The electronic device 600 may obtain image information at pluralviewpoints for the object OBJ by the first sensor 630 and the secondsensor 640 in two different positions, thus obtaining the depthinformation regarding the object OBJ by using various methods dependingon a use environment. The electronic device 600 may obtain the depthinformation regarding the object OBJ by selectively using, for example,structured light or ambient light. That is, image information at aplurality of viewpoints for the object OBJ may be obtained by turningoff the structured light projector 610 and using the ambient light, orby combining image information using the ambient light with imageinformation using the structured light.

The above-described structured light projector may provide structuredlight in a dot pattern suitable for an application requiring thestructured light.

The above-described structured light projector may minimize a devicesize and improve optical efficiency by using an array of subwavelengthnanostructures.

The electronic device employing the above-described structured lightprojector may obtain depth information having improved accuracy for anobject.

Particular executions described in the example embodiments are merelyexamples, and do not limit a technical range with any method. For thesake of brevity, conventional electronics, control systems, softwaredevelopment and other functional aspects of the systems may not bedescribed in detail. Furthermore, the connecting lines, or connectorsshown in the various figures presented are intended to representexemplary functional relationships and/or physical or logical couplingsbetween the various elements.

It should be understood that example embodiments described herein shouldbe considered in a descriptive sense only and not for purposes oflimitation. Descriptions of features or aspects within each embodimentshould typically be considered as available for other similar featuresor aspects in other embodiments.

While example embodiments have been described with reference to thefigures, it will be understood by those of ordinary skill in the artthat various changes in form and details may be made therein withoutdeparting from the spirit and scope as defined by the following claims.

What is claimed is:
 1. A structured light projector comprising: a lightsource configured to emit light; and a nanostructure array configured toform a dot pattern based on the light emitted by the light source, thenanostructure array comprising a plurality of super cells, and each ofthe plurality of super cells comprising a plurality of nanostructures,wherein each of the plurality of super cells comprises a first sub cellthat comprises a plurality of first nanostructures having a first shapedistribution and a second sub cell that comprises a plurality of secondnanostructures having a second shape distribution, and wherein the firstsub cell and the second sub cell are sub-divided areas of each of theplurality of super cells that are different from each other.
 2. Thestructured light projector of claim 1, wherein the light sourcecomprises a plurality of light-emitting elements.
 3. The structuredlight projector of claim 2, wherein the plurality of light-emittingelements and the plurality of super cells are provided intwo-dimensional periodic lattices, respectively.
 4. The structured lightprojector of claim 3, wherein a ratio of a lattice constant of theplurality of light-emitting elements to a lattice constant of theplurality of super cells is a rational number.
 5. The structured lightprojector of claim 3, wherein the two-dimensional periodic lattices ofthe plurality of light-emitting elements and the two-dimensionalperiodic lattices of the plurality of super cells have a same shape anddifferent sizes.
 6. The structured light projector of claim 3, whereinthe two-dimensional periodic lattices of the plurality of light-emittingelements and the two-dimensional periodic lattices of the plurality ofsuper cells have a same shape and a same size.
 7. The structured lightprojector of claim 6, wherein a distance between the light source andthe nanostructure array is an integer multiple of C²/2λ, in which C is alattice constant of a super cell and λ is a central wavelength of thelight emitted by the light source.
 8. The structured light projector ofclaim 1, wherein the first shape distribution and the second shapedistribution are different from each other.
 9. The structured lightprojector of claim 8, wherein the first sub cell and the second sub cellhave equal areas.
 10. The structured light projector of claim 1, whereineach super cell of the plurality of super cells further comprises kthsub cells respectively comprising a plurality of kth nanostructureshaving a kth shape distribution, in which k is an integer from 3 to Nand N is an integer greater than
 3. 11. The structured light projectorof claim 10, wherein the first through Nth sub cells included in eachsuper cell of the plurality of super cells are provided in a twodimensional periodic lattice.
 12. The structured light projector ofclaim 11, wherein each of the first through Nth sub cells included ineach super cell of the plurality of super cells has an areacorresponding to an equally divided area of each super cell of theplurality of super cells.
 13. The structured light projector of claim10, wherein first through Nth shape distributions of the plurality offirst nanostructures through a plurality of Nth nanostructures includedin each of the first through Nth sub cells are different from eachother.
 14. The structured light projector of claim 10, wherein phaseprofiles of the first through Nth sub cells are associated with eachother based on a predetermined rule, and wherein each of the firstthrough Nth sub cells is configured to modulate a phase of incidentlight based on the phase profiles of the first through Nth sub cells,respectively.
 15. The structured light projector of claim 14, wherein aphase profile for an mth sub cell comprises a local phase profile thatis common to the first through Nth sub cells and a global phase profilecorresponding to a position of each super cell of the plurality of supercells in which the mth sub cell is included, in which m is an integerfrom 1 to N and N is an integer greater than or equal to
 3. 16. Thestructured light projector of claim 1, wherein the plurality of firstnanostructures and the plurality of second nanostructures, respectively,have shape dimensions that are less than a wavelength of the lightemitted by the light source.
 17. The structured light projector of claim16, wherein a pitch of the plurality of first nanostructures and a pitchof the plurality of second nanostructures are less than or equal to ½ ofthe wavelength of the light emitted by the light source.
 18. Thestructured light projector of claim 16, wherein a height of each firstnanostructure and a height of each second nanostructure are less than orequal to ⅔ of the wavelength of the light emitted by the light source.19. The structured light projector of claim 1, wherein each of theplurality of first nanostructures and each of the plurality of secondnanostructures comprises a material having a refractive index that isdifferent from a refractive index of a surrounding material by 0.5 ormore.
 20. The structured light projector of claim 1, wherein the dotpattern comprises a random pattern, and wherein the random patterncomprises a plurality of dots forming a cluster that is regularlyarranged.
 21. An electronic device comprising: a structured lightprojector comprising: a light source configured to emit light; and ananostructure array configured to form a dot pattern based on the lightemitted by the light source, the nanostructure array comprising aplurality of super cells, and each of the plurality of super cellscomprising a plurality of nanostructures, wherein each of the pluralityof super cells comprises a first sub cell that comprises a plurality offirst nanostructures having a first shape distribution and a second subcell that comprises a plurality of second nanostructures having a secondshape distribution, and wherein the first sub cell and the second subcell are sub-divided areas of each of the plurality of super cells thatare different from each other; a first sensor configured to receivelight reflected by an object that is irradiated by the light emitted bythe structured light projector; and a processor configured to obtainfirst information regarding a depth position of the object based on thelight received by the first sensor.
 22. The electronic device of claim21, further comprising: a second sensor configured to receive the lightreflected by the object, wherein the processor is further configured toobtain second information regarding the depth position of the objectbased on the light received by the second sensor.
 23. The electronicdevice of claim 22, wherein the processor is further configured toobtain depth information of the object based on at least one of thefirst information and the second information.
 24. A structured lightprojector comprising: a light source configured to emit light, the lightsource comprising a plurality of light-emitting elements; and ananostructure array configured to form a dot pattern based on the lightemitted by the light source and comprising a plurality of super cells,each of the plurality of super cells comprising a plurality of subcells, wherein each of the plurality of super cells comprises a firstsub cell that comprises a plurality of first nanostructures having afirst shape distribution and a second sub cell that comprises aplurality of second nanostructures having a second shape distribution,wherein each of the plurality of sub cells is configured to modulate aphase of light emitted by the light source based on a phase profile ofeach of the plurality of sub cells, and wherein the plurality of subcells are sub-divided areas of each of the plurality of super cells thatare different from each other.
 25. The structured light projector ofclaim 24, wherein the phase profile of each of the plurality of subcells are set based on a predetermined rule corresponding to the dotpattern.
 26. The structured light projector of claim 24, wherein theplurality of light-emitting elements and the plurality of super cellsare provided in two-dimensional periodic lattices, respectively, andwherein the two-dimensional periodic lattices of the plurality oflight-emitting elements and the two-dimensional periodic lattices of theplurality of super cells have a same shape.